Aluminium roofing "slates".

That's bullshit. Most of ours are colored metal.

And the yanks are still into shingles.

More tradition.

I can't quite remember why I asked this question now, it was probably something to do with overall roof weights. But... The reason I was wondering about 'slate sized' tiles of aluminium was because they, I am assuming (so could be wrong) will expand and contract and there might be some issues with the fixing points. I have this idea in my head that the slate-sized tiles would be easier to deal with this expansion and contraction.

Secondly, having the tiles as thick as the slat might improve the noisiness of them? Of this I am absolutely not sure, but I know that a car roof or up & over garage door is far noisier in the rain than a thick piece of metal.

What problems do the metal roof face that reduces this time?

Thanks Colin.